1. Field of the Invention
The present invention relate generally to an apparatus for displacing an extensible/contractible board for a chair. More specifically, the present invention relates to an apparatus for displacing an extensible/contractible board for a chair installed in a theater, a convention hall, a train, an aircraft, a ship or the like particularly in case of an occurrence of emergency, e.g., earthquake, fire or the like. Here, it should be noted that the extensible/contractible board for the apparatus designates such a board that it is forwardly taken out of a hollow space below one elbow rest of the chair when it is put in practical use and it is received in the hollow space when it is not in use.
2. Description of the Background Art
Generally, a number of chairs installed on a theater, a convention hall, a train, an aircraft, a ship or the like are arranged in the transverse direction with a certain distance kept between respective front and rear rows. With such transverse arrangement of the chairs as described above, a space required for installing each chair is effectively utilized, and each transversely extending space between the front and rear rows serves as a passage for allowing users to go forward to look for their seat and leave there later.
In some case, each chair is equipped with an extensible/contractible board having a small area in view of convenience at the time when an user takes a note or eats something. This kind of conventional board is constructed such that it is forwardly taken out of a hollow space below on elbow rest of the chair when it is to be in use and then it continuously maintain a horizontal attitude during his use.
With the conventional extensible/contractible board for a chair, however, it has been found that it has the following drawbacks.
Specifically, when the board is in use, it is projected forwardly of the front surface of the elbow rest while maintaining the horizontal attitude. Thus, the transversely extending passage between front and rear rows is occupied by the projected board. If there arises a necessity for allowing an user sitting on his chair to quickly escape therefrom due to an occurrence of emergency, e.g., earthquake, fire or the like, the projected board becomes an obstacle for him. This may lead to a serious result, e.g., physical hurt or injury of each user.
In addition, when the conventional board receives an excessive magnitude of outer force from the above, there is a danger that components associated with the board to support it are damaged or broken, because they can not absorb the outer force or they can not resist against it. If an unit for preventing these components from being damaged or broken is arranged for the board, the result is that it is unavoidably designed and constructed in larger dimensions at an expensive cost.